He Jingliang

Analysis of a diode-pumped Nd:YVO4 laser passively Q switched with GaAs

Abstract A diode-pumped Nd:YVO4 laser passively Q switched with GaAs is studied theoretically and experimentally. We have demonstrated the influence of single-photon absorption, two-photon absorption and free-carrier absorption in GaAs on the Q-switched pulse characteristics. The pulse profile, pulse energy and pulse width of the Q switching with GaAs are simulated by using the conventional rate equations of the four-level laser system. The experimental results show reasonable agreement with the theoretical results on the whole.

Efficient Diode-Pumped Passively Q-Switched Nd:GdVO4 Lasers

An efficient diode-pumped Nd:GdVO4 laser passively Q-switched by a Cr4+:YAG has been developed as a saturable absorber. A KTP crystal is used for the extra-cavity second-harmonic generation and a BBO crystal for the sum frequency mixing. The green output power is 172 mW at incident pump power of 8 W. The ultraviolet (UV) output power is measured to be 20 mW at the same pump power. The peak power of the UV laser is 143 W with the pulse repetition rate of 14 kHz and pulse width of 10 ns.

Single Pass Third-Harmonic Generation of 310 mW of 355 nm with an All-Solid-State Laser

A maximum of 310 mW average output power at 355 nm has been obtained by extracavity frequency tripling with a BBO crystal in a Q-switched Nd:YVO4 laser with 11.2 W of laser diode pump power. The single pass frequency conversion efficiency (infrared-to-ultraviolet) is 14.3%. The power stability of the ultraviolet laser is better than 1% in 30 min.

Laser-diode pumped Nd: GdVO4 ultraviolet laser with LBO frequency tripling

We have demonstrated a laser-diode pumped Nd: GdVO4 extra-cavity frequency tripling ultraviolet laser with a LBO crystal in this paper. Under the acousto-optic (A-O) Q-switched operation, we have obtained 355 nm ultraviolet laser, with pulse width of 25 ns and pulse repetition rate of 20 kHz. By using a type I non-critical phase-matched LBO crystal, the SHG output power of 822 mW is achieved at the incident pump power of 16 W. The output power of 355nm UV laser is 260mW with a type II phase-matched LBO crystal, and the conversion efficiency (1 064 nm-355 nm) is 5.9 %. The power stability of 355 nm laser is 1.7% in 1 h.

Blue Generation in a Periodically Poled LiTaO3 by Frequency Tripling an 1342 nm Nd:YVO4 Laser

We report on an efficient blue light generation in periodically poled LiTaO3 by the frequency tripling of a quasi-continuous 1342 nm Nd:YVO4 laser. The period of the sample was 14.778 µm. Blue light with an average power of 138 mW was generated from a 18 mm long crystal in a single-pass process under an average fundamental power of 713 mW. The internal conversion efficiency was 19.3%.

Simulation of Patterns and Qualitative Analysis of Pattern Rotation in an End-Pumped Nd:YVO4 Laser

We simulate some laser output patterns observed in our previous experiment employing superposition of Laguerre–Gaussian modes. The rotating pattern is qualitatively analysed from the point of contemporary spatial burning hole effect of the lasing crystal.

DISTORTED WAVE-WAVE PACKET APPROACH TO VIBRATIONAL DEACTIVATION OF DIATOMIC MOLECULE BY COLLISIONS WITH SOLID SURFACE

A model is proposed for vibrational dexcitation of diatomic molecule by collisions with a solid surface, and used to predict the rotational and translational energy distributions and other properties of interest. It is found that molecular rotation dominates over translation in receiving the vibrational energy released, even for the heavier diatomic molecules.